Skid steer loaders are highly maneuverable compact machines. These machines are commonly used in a variety of applications ranging from asphalt milling to earth moving, depending on the job and type of attachment being utilized. Maneuverability is enhanced by balancing the weight ratio between the front and rear axles during loaded and unloaded conditions. Balancing the weight ratio is accomplished, in part, by positioning the engine at the rear of the machine and the load or attachment being carried at the front. Accordingly, it is desirable to provide as compact a machine as possible while maintaining a favorable weight ratio balance.
The engine compartment in a typical skid steer loader is located behind and sometimes extends underneath the operator's compartment. This configuration maintains a favorable weight ratio balance while providing for a compact machine. However, this configuration also leads to a cramped engine compartment. In addition, because of this rear-mounted configuration and the fact that such machines do not typically attain particularly high ground speeds, relatively little air from travel of the machine is available to cool the engine. Cooling systems for existing designs must use a relatively large fan to draw ambient air through a radiator and hydraulic oil cooler and exhaust it out of the engine compartment. Examples of such designs are disclosed generally in U.S. Pat. No. 4,815,550 to Mather or U.S. Pat. No. 6,092,616 to Burris.
Due to increased power requirements and recent and upcoming emissions regulations, the heat load for engine cooling systems has increased. While various engine operating strategies have been developed for reducing emissions, these strategies may require more heat to be rejected by the engine for optimal performance than in traditional designs. For example, air-to-air aftercoolers or other types of heat exchangers may be used to cool incoming turbocharged air. Similarly, as operators demand more comfortable working conditions, air conditioners are used to cool the operator compartment. Both of these components add to the heat load of the cooling system.
While existing cooling systems may adequately satisfy their existing heat loads, they may not be able to handle the increased load from these additional components. Due to spatial constraints in the engine compartment, simply increasing fan size is not always viable. Some off-highway vehicles without the space constraints of a skid steer loader have used remote configurations. For example, an air conditioner condenser and electric cooling fan have been positioned in the operator cabin. Also, the air-to-air aftercooler may be mounted remotely from the main cooling package, such as that described in U.S. Pat. No. 6,546,919 to Callas. However, for a skid steer loader, a remote configuration requires additional fans, increases cost and complexity, and reduces space in an already tight engine compartment.
The present disclosure is directed to overcome one or more of the problems as set forth above.